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Biomedical subjects

S Asano

Publications and source records attributed to S Asano.

At least 397 records · Page 22Linked to original sources
PubMed1990

Clinical usefulness of vinca alkaloid slow infusion in the treatment of chronic refractory idiopathic thrombocytopenic purpura: a multicenter cooperative study.

Thirty-eight patients with chronic refractory idiopathic thrombocytopenic purpura (ITP) were treated with weekly slow infusions of vincristine (0.02 to 0.04 mg/kg) or vinblastine (0.1 to 0.2 mg/kg). Twenty-two patients showed good to excellent responses after one to eight infusions. These responses were generally short, and lasted only in six patients after discontinuance of the therapy. The efficacy was comparable between vincristine and vinblastine. Neither the age, sex, duration of the disease, prior splenectomy nor combined use of adrenocortical steroids was likely to have influenced the therapeutic effect. Side effects such as peripheral neuropathy, alopecia, gastrointestinal symptoms and leukopenia occurred in 34 patients, and necessitated discontinuance of the therapy in eight patients. Slow infusions of vinca alkaloids can be an effective means of inducing platelet response in patients with chronic refractory ITP, but frequent side effects limit its clinical usefulness.

Adolescent↗
PubMed1989

Human granulocyte colony-stimulating factor specifically binds to murine myeloblastic NFS-60 cells and activates their guanosine triphosphate binding proteins/adenylate cyclase system.

The specific binding of human granulocyte colony-stimulating factor (G-CSF) to its receptors on NFS-60 cells acts as a primer for cellular proliferation. There are approximately 400 binding sites per cell, with a binding constant of about 100 pmol/L. Before the proliferative response, the affinity constant of the membrane particulate fraction to 35S-labeled guanosine triphosphate-gamma-S (35S-GTP gamma S) and the intracellular cyclic adenylate monophosphate (cAMP) level increased in the presence of G-CSF to about 2.5-fold and about fivefold higher, respectively, than the levels seen in the absence of G-CSF. The increases were time-dependent, with a peak occurring 15 minutes after the addition of G-CSF at 37 degrees C. These findings suggest that, following the binding of the G-CSF to its surface receptors, the activation of the guanosine triphosphate (GTP)-binding protein/adenylate cyclase system may be involved in the proliferation of immature myeloid cells.

Adenylyl Cyclases↗
PubMed1989

Paraneoplastic syndrome of hypercalcemia and leukocytosis caused by squamous carcinoma cells (T3M-1) producing parathyroid hormone-related protein, interleukin 1 alpha, and granulocyte colony-stimulating factor.

Previously we reported that a clonal squamous cell carcinoma cell line (T3M-1) derived from a lower jaw cancer of a patient with marked leukocytosis and hypercalcemia produced factors containing a potent bone-resorbing activity (BRA) (Mr 15,000-20,000) and a colony-stimulating activity. To elucidate the pathogenesis of this humoral hypercalcemia, BRA and colony-stimulating activity in both the conditioned medium and cells were characterized. The conditioned medium, when eluted at neutral pH, contained colony-stimulating activity and thymocyte proliferation-stimulating activity, the latter of which comigrated with BRA. Upon elution with acetic acid (pH 2.0), the conditioned medium contained no interleukin 1-like activity but potent parathyroid hormone-like activity, which comigrated with BRA. Northern blot hydridization analysis revealed that T3M-1 cells produced constitutively mRNA for parathyroid hormone-related protein and granulocyte colony-stimulating factor. Furthermore, primer extension analysis revealed that the cells also produced mRNA for interleukin 1 alpha (IL-1 alpha). Since parathyroid hormone-related protein and IL-1 alpha (osteoclast-activating factor) synergistically increase the concentration of serum calcium, and since IL-1 alpha (hemopoietin 1) potentiates granulocyte colony-stimulating factor-induced granulocytopoiesis, we speculate that parathyroid hormone-related protein, granulocyte colony-stimulating factor, and IL-1 alpha are synergistically involved in a paraneoplastic syndrome of hypercalcemia and leukocytosis, at least in some patients with solid tumors.

Animals↗
PubMed1989

The primary structure of thermostable D-amino acid aminotransferase from a thermophilic Bacillus species and its correlation with L-amino acid aminotransferases.

The gene for thermostable D-amino acid aminotransferase from a thermophile, Bacillus species YM-1 was cloned and expressed efficiently in Escherichia coli. The entire covalent structure of the enzyme was determined from the nucleotide sequence of the cloned gene and mostly confirmed by amino acid sequences of tryptic peptides from the gene product. The polypeptide is composed of 282 amino acid residues with a calculated molecular weight of 32,226. Comparison of the primary structure with those of various proteins registered in a protein data bank revealed a significant sequence homology between D-amino acid aminotransferase and the L-branched chain amino acid aminotransferase of E. coli (Kuramitsu, S., Ogawa, T., Ogawa, H., and Kagamiyama, H. (1985) J. Biochem. (Tokyo) 97, 993-999); the active site lysyl residue is located in an equivalent position in both enzyme sequences of similar size. Despite the difference in subunit composition and no immunochemical cross-reactivity, the sequences of the two enzymes show similar hydropathy profiles, and spectrophotometric properties of the enzyme-bound cofactor are also similar. The sequence homology suggests that the structural genes for D-amino acid and L-branched chain amino acid aminotransferases evolved from a common ancestral gene.

Amino Acid Sequence↗
PubMed1989

Thermostable D-amino acid aminotransferase from a thermophilic Bacillus species. Purification, characterization, and active site sequence determination.

D-Amino acid aminotransferase was found in several thermophilic Bacillus species and purified to homogeneity from the best producer, Bacillus sp. YM-1, which was newly isolated from a sauna dust. The enzyme has a molecular weight of about 62,000 and consists of two subunits identical in molecular weight (30,000). It catalyzes transamination between various D-amino acids and alpha-keto acids, although the substrate specificity is narrower than the enzyme from the mesophile, Bacillus sphaericus (Yonaha, K., Misono, H., Yamamoto, T., and Soda, K. (1975) J. Biol. Chem. 250, 6983-6989). The Bacillus sp. YM-1 enzyme is most active at 60 degrees C and stable at high temperatures. Automated Edman degradation provided the N-terminal sequence of the first 20 amino acids, and carboxypeptidase Y digestion provided the C-terminal sequence of the last 3 amino acids. The amino acid sequence in the vicinity of the lysyl residue, Lys(Pxy), that binds pyridoxal 5'-phosphate was determined as Cys-Asp-Ile-Lys(Pxy)-Ser-Leu-Asn-Leu-Leu-Gly-Ala-Val-Leu-Ala-Lys- from the pyridoxyl peptide obtained by digestion with trypsin. The active site sequence is markedly different from those of L-amino acid aminotransferases and other pyridoxal 5'-phosphate-dependent enzymes.

Amino Acid Sequence↗
PubMed1989

Site-directed mutagenesis of the cysteinyl residues and the active-site serine residue of bacterial D-amino acid transaminase.

Each of the three cysteinyl residues per subunit in D-amino acid transaminase from a thermophilic species of Bacillus has been changed to a glycine residue (C142G, C164G, and C212G) by site-directed mutagenesis. The mutant enzymes were detected by Western blots and a stain for activity. After purification to homogeneity, each mutant protein had the same activity as the wild-type enzyme. Thus, none of the Cys residues are essential for catalysis. Each protein when denatured showed the expected titer of two SH groups per subunit. In the native state, each of the three mutant proteins exhibited nearly the same slow rate of titration of SH groups as the wild-type protein with about one SH group titratable over a period of 4 h. Conversion of Ser-146, adjacent to Lys-145 to which the coenzyme pyridoxal phosphate is bound, to an alanine residue (S146A) does not alter the catalytic activity but has a significant effect on the SH titration behavior. Thus, three to four of the six SH groups of S146A are titratable by DTNB. The rapid SH titration of S146A is prevented by the presence of D-alanine. This finding suggests that the change of Ser-146 to Ala at the active site promotes the exposure and rapid titration of a Cys residue in that region. The rapid SH titration of S146A by DTNB is accompanied by a loss of enzyme activity. Two of the mutant enzymes, C142G and S146A, lose activity at 4 degrees C and also upon freezing and thawing. The mutant enzymes C164G and C212G show the same degree of thermostability as the wild-type enzyme.

Bacillus↗
PubMed1989

Activity and spectroscopic properties of bacterial D-amino acid transaminase after multiple site-directed mutagenesis of a single tryptophan residue.

One of the three tryptophan residues per subunit of thermostable D-amino acid transaminase, Trp-139, is close to the active-site Lys-145 in the sequence of the protein. This tryptophan has been changed to several other types of residues by site-directed mutagenesis. The only mutant protein that was sufficiently active and stable for study had Phe substituted for Trp (W139F). The spectroscopic properties of this mutant enzyme differed from those of the wild-type transaminase. For example, denatured W139F showed the expected decrease in fluorescence emission intensity at 350 nm due to the deletion of one Trp residue, but the fluorescence emission of the wild-type and W139F enzymes in the native state did not differ in intensity. This result suggests that the fluorescence of Trp-139 in the native, wild-type enzyme is not manifested perhaps due to its proximity to the coenzyme, pyridoxal phosphate. Results of energy-transfer studies at several wavelengths could also be interpreted as due to the proximity of Trp-139 and the coenzyme. Circular dichroism studies indicated that the negative Cotton effect at 420 nm due to the coenzyme was still present in W139F. However, the 280-nm optically active band present in the wild-type enzyme was greatly diminished in W139F. The mutant protein with Asp at position 139 (W139D) could not be isolated presumably because it was degraded. The other mutant enzymes, W139P, W139A, and W139H, were isolated with partial activities (15-35%) that were slowly lost upon storage at 4 degrees C. Overall, these results indicate the importance of Trp-139 in the thermostable D-amino acid transaminase.

Bacillus↗
PubMed1989

Erythrocyte enzyme activities in myelodysplastic syndromes: elevated pyruvate kinase activity.

The erythrocyte enzyme activities in twenty-six cases of myelodysplastic syndromes were determined. There were remarkably abnormal levels in seven cases; namely, four cases showed increased hexokinase activity, three cases showed increased pyruvate kinase activity, and two cases showed increased adenosine deaminase activity. Among these, one case with elevated pyruvate kinase activity showed the novel expression of M2-type pyruvate kinase activity, in addition to the R-type pyruvate kinase activity normally found in erythrocytes. Southern blotting of peripheral leucocyte DNA revealed only an amplified PK-LR genome, which derived from the chromosomal abnormality of a 1;7 translocation. The mechanism responsible for switching M2-type to R-type during erythroid maturation was considered to be partially disrupted in this case.

Blotting, Southern↗
PubMed1989

Dermatoses among poultry slaughterhouse workers.

A survey on the incidence of occupational dermatoses among poultry slaughterhouse workers, who, in order to do their work more efficiently, protected their hands only with cotton gloves, revealed that many workers had dermatoses of the hands. Their symptoms included maceration, erosio interdigitalis, paronychia, trichophytia unguium, and eczema, presumably caused by the constant wetness of their hands during work. Candida albicans was detected in the ungual lesions of some patients. A second survey including a skin examination was performed at a plant where preventive measures such as better working gloves and improved sanitary conditions had been implemented because of the high incidence of skin disorders. The results of this survey showed marked improvement in the reduction of the incidence of dermatoses.

Abattoirs↗
PubMed1989

Mesodermal mixed tumor primary in the fallopian tube.

Mullerian mixed tumors, as a group, are uncommon. Only 27 cases of this tumor of the fallopian tube have been reported to date. We report the 28th case of mixed mesodermal tumor, originating in the fallopian tube. A 79-year-old woman had mistaken a bloody vaginal discharge for hematuria. Various examinations showed no evidence of malignancy. However, computerized tomography revealed an intrapelvic tumor. Laparotomy was performed, with a suspicion of tubal malignancy. The final pathologic diagnosis was mixed mesodermal tumor, originating in the fallopian tube. Postoperatively, the patient was placed on oral adjuvant chemotherapy for 34 months. At present, she is doing well. Though no definite conclusions regarding the best method of therapy can be reached, an aggressive mode of therapy is recommended. The primary therapy is surgery; however, surgery followed by chemotherapy may have a potential benefit.

Aged↗
PubMed1989

Endobronchial non-Hodgkin's lymphoma.

A 64-year-old man with non-Hodgkin's lymphoma suffered a complete collapse of the left upper lobe of the lung. Fibreoptic bronchoscopy demonstrated a large number of distinct polypoid tumours of the lymphoma in the trachea and bilateral sub-segmental bronchi. The left upper lobe bronchus was completely occluded by the tumours, which responded to the combination chemotherapy against the lymphoma. This report presents the seventh case of non-Hodgkin's lymphoma with multiple endobronchial tumours.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

Monoclonal antibody HK4001 completely inhibits K(+)-dependent ATP hydrolysis and H+ transport of hog gastric H+,K(+)-ATPase.

A monoclonal antibody (designated as HK4001) was prepared against hog gastric H+,K(+)-ATPase. It dose-dependently inhibited the H+,K(+)-ATPase activity, formation of the K(+)-sensitive phosphoenzyme, and proton uptake into gastric vesicles. The H+,K(+)-ATPase activity was completely inhibited by addition of the antibody at a molar ratio of 1:2 (antibody/catalytic subunit) at pH 7.8. The maximal inhibition decreased with decrease in pH of the medium (7.8 greater than 7.4 greater than 6.2). The Fab fragment obtained by digestion of the antibody with papain was also inhibitory. The antibody did not inhibit the K(+)-dependent p-nitrophenylphosphatase or the labeling of the enzyme with fluorescein isothiocyanate. It inhibited gastric H+,K(+)-ATPase from rabbits and rats, but did not cross-react with related cation-transport ATPases (Na+,K(+)-ATPase or Ca2(+)-ATPase) or H(+)-ATPase in the multivesicular body. From these and related findings, the antibody was suggested to recognize a highly specific site on the cytosolic surface of H+,K(+)-ATPase. The conformation of the epitope was conserved after treatment with Triton X-100, but not sodium dodecyl sulfate. In addition, judging from the stoichiometry of inactivation of H+,K(+)-ATPase by this antibody, the functional unit of H+,K(+)-ATPase was suggested to be a dimer or a tetramer (not a trimer) of the catalytic unit.

Adenosine Triphosphatases↗